cborutil: port to Python 3

The only problem lurking in here was sorts of mismatched types. The
sorts are only for output stability in our tests (sigh), so we just
build a phony sort key using the __name__ of types so that we only
compare like types against each other. By pure luck, my awful sort key
matches the behavior we get "for free" in Python 2, so no test output
changes.

Differential Revision: https://phab.mercurial-scm.org/D3504

mercurial/utils/cborutil.py

@@ -140,12 +140,15 b' def streamencodearrayfromiter(it):'
 
     yield BREAK
 
+def _mixedtypesortkey(v):
+    return type(v).__name__, v
+
 def streamencodeset(s):
     # https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml defines
     # semantic tag 258 for finite sets.
     yield encodelength(MAJOR_TYPE_SEMANTIC, 258)
 
-    for chunk in streamencodearray(sorted(s)):
+    for chunk in streamencodearray(sorted(s, key=_mixedtypesortkey)):
         yield chunk
 
 def streamencodemap(d):
@@ -155,7 +158,8 b' def streamencodemap(d):'
     """
     yield encodelength(MAJOR_TYPE_MAP, len(d))
 
-    for key, value in sorted(d.iteritems()):
+    for key, value in sorted(d.iteritems(),
+                             key=lambda x: _mixedtypesortkey(x[0])):
         for chunk in streamencode(key):
             yield chunk
         for chunk in streamencode(value):